Current telecommunication systems for cellular applications include analog and digital systems. Analog cellular systems, which currently dominate cellular transmission systems, use a variety of different protocols. Two known analog cellular data systems include a cellular modem system and a cellular digital packet data system ("CDPD", hereafter). Analog cellular data systems have a variety of problems including low bandwidth and costly hardware requirements.
With the cellular modem system, the main drawback of the system is its low throughput, typically in the range of 4800 to 9600 bits per second. Moreover, due to the noisy environment of the cellular modem system, achieving the maximum throughput of over 9000 bits per second is difficult. Another drawback of cellular modem systems is that they require a permanent connection between the base and the mobile system. This requirement increases the cost for the end user.
The main drawback with the CDPD system is the substantial system costs. The CDPD system is not restricted to a specific voice channel, and does not require a permanent connection, a dedicated channel, between the base and mobile system. However, the CDPD system requires that every base station has a hardware update to incorporate CDPD site functionality. This update substantially increases the investment in infrastructure costs for the cellular service provider.
Emerging and existing data communications applications require large bandwidths to exchange information. For instance, effective wireless access to the Internet, the World Wide Web, and other information systems requires the availability of large bandwidths. However, as has been described, current systems have unacceptably low bandwidths or require significant capital expenditures. Therefore, a need exists to increase the bandwidth of analog cellular systems without requiring costly new hardware installations to base stations or cell sites.